FiTech EFI system

Initial fire up on my 440 engine was not at all the desired out come I was looking for.
The engine spit and sputtered and would not idle at all. I had to hold my foot on the accelerator to keep it running . I set the handheld to the setting I wanted and had to reset it twice and I was sure to hit enter after each setting .But just when I was cursing fitech and threating to call them in the morning. I read were it says some engine may require an idle screw adjustment . I would recommend everyone do this before the initial fire. after I did this adjustment the car fired and ran. The idle was erratic and would go from 900 to 2000 to 1500 and settled at the 1000 that I had input . So at that point I was tired and went to bed. This morning I went out and hit the key and it fired instantly and idle was perfect after warm up I hit the accelerator and it took awhile for the rev to come back to normal. I expect it may be still be learning. On the control it says its trying to hit a 13.80 afr is that would it should be ? I'm loving it though there was no holding the throttle till warm up to get it to idle just hit the key and wham bam thank you mam she fired and idle perfect. Until I hit it and it still take awhile to get back to normal idle. Any input ?